Under the related art, vacuum pumps powered directly by the combustion engine are operated as wet-running pumps. Engine oil is used for lubrication, sealing and cooling. When dry-running pumps are used, one encounters the problem of dissipating the heat generated by friction and compression, especially at high speeds.
Also known from the related art are pumps, commonly referred to as scroll compressors, for example, which have costly cooling devices on the housing that require a large installation volume.